The blood film of a patient with either hereditary stomatocytosis or Southeast Asian ovalocytosis will show stomatocytes as a common feature. There are however important differences in the red cell parameters that permit one to differentiate morphologically between the two disorders. Hereditary stomatocytosis, often referred to as hereditary hydrocytosis, is…

A 30 years old pregnant female presented with severe preeclampsia at 35 weeks gestation. A full blood count and clinical chemistry profile were performed and the following results noted: Hb…

A 58 years old female presents with a history of fatigue, easy bruising and recurrent infection. She is found to have gross splenomegaly. A full blood count is performed and the following results noted: Hb 143 g/L, WBC 45.0 x 109/L and platelet count 91 x 109/L. The peripheral blood…

A 1 day old neonate presents with extreme jaundice at birth. A full blood count and chemistry profile are performed with the following results: WBC 20.7 x 109/L, Hb 114 g/L, MCV 86.0 fL, MCH 28.5 pg and platelet count 243 x 109/L. Total bilirubin 403 µmol/L and conjugated bilirubin…

A 50 year old female presents with lethargy, bruising and bleeding gums. A full blood count is performed and the following results noted: Hb 74 g/L      WBC 2.3 x 109/L      Platelet count 28 x 109/L. The coagulation results are: PT 16.9 sec      INR 1.3      APTT 27.1…

A 12 months old child presents with an acute febrile illness. A full blood count, ESR and blood cultures are performed and the following results noted: Hb 90 g/l, WBC 18.6 x 109/l, Platelet count 720 x 109/l and ESR 110 mm/hr. The blood cultures show no growth after 7 days. The blood film shows a normochromic, normocytic anaemia with marked rouleaux formation. The neutrophils show increased granulation and vacuolation. They also show cytoplasmic swelling, a characteristic feature of Kawasaki disease. A marked thrombocytosis is present. Could the diagnosis be sepsis or could it be Kawasaki disease? What is Kawasaki disease? In 1967, Tomisaku Kawasaki, a Japanese paediatrician, described 50 children with fever lasting for more than 5 days. The children had cervical lymphadenopathy, rash, bilateral non-exudative conjunctivitis, swelling of the hands and feet and inflammation of the oral mucosa. The children ranged in age from 6-12 months.

Kawasaki disease is more common amongst males with a male-to-female ratio of 1.5:1. The etiology of Kawasaki disease is still not understood. It is thought to be a multisystem vasculitic disorder. The onset of the fever is abrupt. It is a high, sustained fever, unresponsive to antibiotic therapy, lasting for a week or longer. During the acute phase, Kawasaki disease may cause medium and large vessel arteritis, arterial aneurysms, valvulitis and myocarditis. If untreated, approximately 20% of patients will develop coronary aneurysms. Kawasaki disease has surpassed rheumatic fever as the leading cause of heart disease in children less than 5 years of age. The medical management of Kawasaki disease involves the use of intravenous gamma globulin as well as aspirin, which is used as an anti-inflammatory agent. Kawasaki disease is diagnosed from a combination of clinical and haematological features. Bacterial sepsis must always be excluded. Scientists working with paediatric patients should be ever mindful of this potentially fatal disease.

A 5 year old boy presents with malaise, pallor and fever. On clinical examination he has hepatosplenomegaly and lymphadenopathy. He also has neurofibromatosis. A full blood count is performed and the following results noted: Hb 99 g/L, WBC 27.4 x 109/L and platelet count 206 x 109/L The differential white cell count shows a left shift and a monocytosis of 11.5 x 109/L. A bone marrow aspiration is performed revealing an increase in myelopoiesis as well as a monocytosis. Cytogenetic studies demonstrate a monosomy 7. The HbF is raised at 6.4% (normal range for age is <1%). A diagnosis of juvenile myelomonocytic leukaemia (JMML) is made. JMML was classified as a myelodysplastic syndrome (MDS) by the FAB classification. The World Health Organization (WHO) removed JMML from the MDS classification and placed it in a new category, namely Myelodysplastic/Myeloproliferative Diseases (MDS/MPD). JMML typically presents in children less than 4 years of age, with

most cases occurring under the age of 2 years. The disease is more common in males than females (male to female ratio approximately 2.5:1). JMML is a clonal disease characterized by an elevated WBC that is usually less than 100 x 109/L with a left shift in the myeloid line. There is a peripheral monocytosis of more than 1 x 109/L with less than 20% blasts in the peripheral blood and bone marrow. The HbF is raised for the age of the child. The bone marrow is hypercellular with myeloid hyperplasia and decreased numbers of megakaryocytes. JMML lacks the Philadelphia chromosome or BCR / ABL fusion gene. Although cytogenetic abnormalities, including monosomy 7, occur in 30% to 40% of cases, no specific cytogenetic abnormality characterises JMML. JMML is associated with the autosomal dominant neurogenetic disorder neurofibromatosis. Children with neurofibromatosis type 1 (NF1) are at increased risk for developing JMML. Most cases of JMML have a mean survival between 1 and 2 years. Death is usually due to infection…

A 10-month-old male child presented with a one-day history of fever. The child was noted to be pale and lethargic. A full blood count was performed and the following results were noted: Hb 40 g/L, MCV 99 fL (normal range for age 70-83 fL), WCC 9.5 x 109/L and platelet count 42 x 109/L The blood film showed the presence of oval macrocytes, hypersegmented neutrophils and circulating megaloblasts. Further investigations revealed a low serum folate of 2.1 nmol/L (NR 5.5-33.3) and a low vitamin B12 level of 103 pmol/L (NR 109-646). Iron studies were within normal limits. A diagnosis of megaloblastic anaemia secondary to nutritional folate and vitamin B12 deficiency was made. Megaloblastic anaemia in children is usually due to a lack of vitamin B12 and/or folic acid either through poor diet, increased cell turnover or malabsorption. Vitamin B12 and folic acid are prerequisites for DNA synthesis and thus the production of normocytic haematopoiesis. In their absence, the peripheral

blood is characterised by the presence of oval macrocytes, teardrop poikilocytes and hypersegmented neutrophils. Basophilic stippling and Howell Jolly bodies may also be present. The mean cell volume in this child is raised for age. The bone marrow is hypercellular with increased numbers of megaloblasts which show asynchrony of nuclear and cytoplasmic maturation. The nuclei maintain a primitive, open chromatin pattern while the cytoplasm matures normally. Giant metamyelocytes and hypersegmented neutrophils are also present. The megakaryocytes show hypersegmented nuclei with an open chromatin pattern. Megaloblastic anaemia due to inadequate dietary intake may coexist with iron deficiency. Vitamin B12 deficiency in infancy may lead to irreversible neurological damage. Iron deficiency, often seen more commonly in this age group, can also result in less severe, but similarly irreversible neurological damage. Iron deficiency is usually secondary to excessive cow's milk and inadequate ingestion of solids. Further discussion with this child's parents revealed that the child was breast fed for the first 2 weeks of…

A 15 year old male presented with lethargy, pallor and bleeding from the gums. A full blood count was performed with the following results: Hb 44 g/L, WCC 53.7 x 109/L and platelet count 12 x 109/L The differential white cell count showed an absolute monocytosis of 10.7 x 109/L and a blast count of 22.5 x 109/L. A bone marrow examination revealed a hypercellular marrow with 74% blast cells. The blasts had a round to convoluted nuclear appearance with a fine chromatin pattern and one or more nucleoli. The cytoplasm was basophilic and lacked granules. Morphologically, they resembled monoblasts. Flow cytometry was performed on the marrow, which had the following immunophenotype: CD13+/CD33+/CD34-/CD117+/HLA-DR+/TdT-/MPO+ (myeloid markers) CD14-/CD64+/CD116+ (monocytoid markers) The markers were suggestive of acute myeloid leukaemia with monocytic differentiation. As the blasts clearly resembled monoblasts morphologically, a combined esterase stain was performed. The blasts were positive with the a-naphthyl acetate esterase stain and negative with the AS-D chloroacetate esterase stain. The

overwhelming brown reaction, as seen below, confirmed the morphological diagnosis of acute monoblastic leukaemia. Acute monoblastic leukaemia The WHO classification of acute monoblastic leukaemia, synonymous with M5a in the FAB classification, occurs at any age but most commonly occurs in young adults. The majority of cases present with bleeding gums secondary to gingival infiltration. Acute monoblastic leukaemia and acute monocytic leukaemia are myeloid leukaemias characterised by 80% or more cells of the monocytic lineage. In acute monoblastic leukaemia, at least 80% of the cells are monoblasts and in acute monocytic leukaemia, at least 80% of the cells are promonocytes and monocytes. Monoblasts have rounded nuclei with a fine chromatin pattern and one or two prominent nucleoli. The cytoplasm is basophilic and lacks granules. Promonocytes show some differentiation in the maturation of the nucleus, which is indented and often contains a nucleolus. The cytoplasm is blue-grey and may contain a few fine azurophilic granules as well as vacuoles. Monoblasts and…

A 3-year-old child presented with pallor and lethargy. A full blood count was performed and the following results were noted: Hb 43 g/L, MCV 75.3 fL, WCC 5.3 x 109/L and platelet count 302 x 109/L. Although the white cell count was normal, the differential revealed a mild neutropenia of 1.0 x 109/L. A haemolytic screen was performed: the reticulocyte count was 0.1%, the bilirubin 10 umol/L and the serum lactate dehydrogenase 202 IU/L. Initial serology testing for parvovirus B19 infection was negative. A bone marrow examination revealed a mildly hypocellular marrow with marked erythroid hypoplasia. Myeloid maturation, despite a mild neutropenia, was normal. As the Hb and reticulocyte count improved spontaneously within a few days, a diagnosis of ‘transient erythroblastopenia of childhood’ was made retrospectively on this child. Transient erythroblastopenia of childhood There are 3 major causes of red cell aplasia occurring in childhood. They are namely: Diamond-Blackfan anaemia (DBA) or pure red cell

aplasia Transient erythroblastopenia of childhood (TEC) Acute aplastic crisis superimposed on chronic haemolytic anaemia. This form of red cell aplasia may occur in adults as well as in children. In 1970, Wranne described 4 children with temporary red cell aplasia. This phenomenon became known as ‘transient erythroblastopenia of childhood’ or TEC. TEC commonly presents at 2 years of age, although it can present as young as 6 months of age. The clinical presentation of TEC is essentially normal except for the appearance of pallor and signs of anaemia such as tachycardia. The Hb levels are variable with a mean of 56 g/L and a reticulocyte count below 1.0%. If the patient is already in the recovery phase, which frequently occurs, the reticulocyte count will be higher. TEC is often associated with a neutropenia. Bone marrow examination reveals a normocellular marrow with erythroid hypoplasia. Myeloid maturation is normal despite the frequent association with neutropenia. Serum lactate dehydrogenase, bilirubin and serum haptoglobin levels are normal in TEC…